In recent years, there have been provided high-performance liquid crystal display devices, each of which includes a liquid crystal display panel to which a touch panel function is imparted in addition to an information displaying function so as to improve convenience for users (for example, refer to Patent Literature 1).
A specific example of such liquid crystal display devices is the one including (i) a liquid crystal display panel serving as a display section in which information including characters and images is displayed and (ii) a touch panel assembled to a display surface or to a surface opposite to the display surface of the liquid crystal display panel.
Because of its information displaying function achieved by the liquid crystal display panel and its another function of receiving input via the touch panel, such a liquid crystal display device is capable of providing users with various services such as displaying of information corresponding to input of instructions by the uses.
Specifically, the liquid crystal display device is configured such that (i) the liquid crystal display device displays an input screen on the display surface of its liquid crystal display panel and (ii) the touch panel detects an input operation carried out by a user with respect to the input screen. The liquid crystal display device is arranged such that user's desired information can be displayed by changing, according to the result of detection by the touch panel, the input screen displayed on the display surface to a screen showing information that the user instructed via the input screen.
Meanwhile, a high-value-added liquid crystal display device, which includes an in-cell capacitive touch panel (multi-touch) in a liquid crystal display panel, is highly likely to be produced, and is expected to be able to significantly reduce the number of steps and material costs as compared to a conventional liquid crystal display device having a touch panel function. The following description discusses such a liquid crystal display device.
FIG. 11 is a view schematically illustrating a configuration of the aforementioned liquid crystal display device. As illustrated in FIG. 11, this liquid crystal display device 500 includes a liquid crystal display panel 505 and a touch panel 506. The liquid crystal display panel 505 is constituted by a TFT substrate 501, a color filter substrate 502 and a glass substrate 503. The touch panel 506 is constituted by the glass substrate 503 and a protection film 504.
As illustrated in FIG. 11, the liquid crystal display device 500 is configured such that the liquid crystal display panel 505 and the touch panel 506 are arranged in this order. As described earlier, the touch panel 506 is an in-cell touch panel included in the liquid crystal display panel 505.
According to this configuration, alignment is required between an existing pattern on the color filter substrate 502, which existing pattern is positioned on the back surface-side of the glass substrate 503, and a design pattern under the protection film 504, which design pattern is positioned on the front surface-side of the glass substrate 503. This is to optimally set the relative position of the patterns. The following description discusses such alignment.
FIG. 12 is a view for describing alignment between the back surface-side and the front surface-side of the glass substrate 503. As illustrated in FIG. 12, an alignment mark 51 is provided on the color filter substrate 502. The alignment mark 51 is in the shape of a cross when viewed from above (refer to I in FIG. 12).
A design pattern on the glass substrate 503 is aligned with the alignment mark 51 which serves as a reference.
On the glass substrate 503, a design pattern optimally positioned relative to the alignment mark 51 is formed. The design pattern includes an alignment mark 52. The alignment mark 52 is also in the shape of a cross when viewed from above (refer to J in FIG. 12).
Such alignment marks 51 and 52 can be formed for example in the following manner. FIG. 13 is a view for describing the steps of forming the alignment marks 51 and 52.
First, as illustrated in (a) of FIG. 13, a metal film 52b is stacked on the glass substrate 503. The metal film 52b is stacked on the entire surface of the glass substrate 503.
Next, as illustrated in (b) of FIG. 13, a resist pattern 53 is formed on the metal film 52b. The resist pattern 53 is a pattern for removing the metal film 52b which is stacked above an alignment region where a plurality of alignment marks 51 are provided on the color filter substrate 502. Note that a design pattern of the resist pattern 53 is not aligned with the alignment mark 51 which serves as a reference.
Next, as illustrated in (c) of FIG. 13, the metal film 52b is removed according to the resist pattern 53. That is, the metal film 52b above the alignment region of the color filter substrate 502 is removed. After the metal film 52b is removed in this manner, the resist pattern 53 is removed.
Next, as illustrated in (d) of FIG. 13, a resist pattern 54 is formed on a remaining metal film 52b. The resist pattern 54 is a pattern for forming the alignment mark 52. A design pattern of the resist pattern 54 is aligned with the alignment mark 51 which serves as a reference.
Next, as illustrated in (e) of FIG. 13, the metal film 52b is removed according to the resist pattern 54. That is, the alignment mark 52 is formed on the glass substrate 503.
Next, as illustrated in (f) of FIG. 13, after the metal film 52b is removed, the resist pattern 54 is removed.
Lastly, as illustrated in (g) of FIG. 13, the protection film 504 is stacked on the glass substrate 503 and the alignment mark 52.
Alternatively, the alignment marks 51 and 52 as shown in FIGS. 11 and 12 can be formed in the following manner. FIG. 14 is a view for describing the steps of forming the alignment marks 51 and 52.
First, as illustrated in (a) of FIG. 14, a metal film 52b is stacked on the glass substrate 503. The metal film 52b is stacked under the condition where a stack prevention mask 55 is provided above the alignment region of the color filter substrate 502 so that no metal film 52b is stacked above the alignment region. Since the alignment region of the color filter substrate 502 is hidden behind the stack prevention mask 55 when viewed from above, no metal film 52b is stacked above the alignment region.
Next, as illustrated in (b) of FIG. 14, after the metal film 52b is stacked, the stack prevention mask 55 is removed.
Next, as illustrated in (c) of FIG. 14, a resist pattern 54 is formed on the metal film 52b. The resist pattern 54 is a pattern for forming the alignment mark 52. A design pattern of the resist pattern 54 is aligned with the alignment mark 51 which serves as a reference.
Next, as illustrated in (d) of FIG. 14, the metal film 52b is removed according to the resist pattern 54. That is, the alignment mark 52 is formed on the glass substrate 503.
Next, as illustrated in (e) of FIG. 14, after the metal film 52b is removed, the resist pattern 54 is removed.
Lastly, as illustrated in (f) of FIG. 14, the protection film 504 is stacked on the glass substrate 503 and the alignment mark 52.
Further, there is another kind of the aforementioned liquid crystal display device as below. FIG. 15 is a view schematically illustrating another configuration of the aforementioned liquid crystal display device. As illustrated in FIG. 15, this liquid crystal display device 600 includes a touch panel 605 and a liquid crystal display panel 606. The touch panel 605 is constituted by a protection film 601 and a glass substrate 602. The liquid crystal display panel 606 is constituted by the glass substrate 602, a color filter substrate 603 and a TFT substrate 604.
As illustrated in FIG. 15, the liquid crystal display device 600 is configured such that the touch panel 605 and the liquid crystal display panel 606 are arranged in this order. As described earlier, the touch panel 605 is an in-cell touch panel included in the liquid crystal display panel 606.
According to this configuration, alignment is required between an existing pattern on the protection film 601, which existing pattern is positioned on the back surface-side of the glass substrate 602, and a design pattern under the color filter substrate 603, which design pattern is positioned on the front surface-side of the glass substrate 602. This is to optimally set the relative position of the patterns. The following description discusses the alignment.
FIG. 16 is a view for describing alignment between the back surface-side and the front surface-side of the glass substrate 602. As illustrated in FIG. 16, an alignment mark 61 is provided on the protection film 601. The alignment mark 61 is in the shape of a cross when viewed from above (refer to K in FIG. 16).
A design pattern on the glass substrate 602 is aligned with the alignment mark 61 which serves as a reference.
On the glass substrate 602, a design pattern optimally positioned relative to the alignment mark 61 is formed. The design pattern includes an alignment mark 62. The alignment mark 62 is also in the shape of a cross when viewed from above (refer to L in FIG. 16).
Such alignment marks 61 and 62 can be formed for example in the following manner. FIG. 17 is a view for describing the steps of forming the alignment marks 61 and 62.
First, as illustrated in (a) of FIG. 17, a metal film 62b is stacked on the glass substrate 602. The metal film 62b is stacked on the entire surface of the glass substrate 602.
Next, as illustrated in (b) of FIG. 17, a resist pattern 63 is formed on the metal film 62b. The resist pattern 63 is a pattern for removing the metal film 62b which is stacked above an alignment region where a plurality of alignment marks 61 are provided on the protection film 601. Note that a design pattern of the resist pattern 63 is not aligned with the alignment mark 61 which serves as a reference.
Next, as illustrated in (c) of FIG. 17, the metal film 62b is removed according to the resist pattern 63. That is, the metal film 62b above the alignment region of the protection film 601 is removed. After the metal film 62b is removed in this manner, the resist pattern 63 is removed.
Next, as illustrated in (d) of FIG. 17, a resist pattern 64 is formed on a remaining metal film 62b. The resist pattern 64 is a pattern for forming the alignment mark 62. A design pattern of the resist pattern 64 is aligned with the alignment mark 61 which serves as a reference.
Next, as illustrated in (e) of FIG. 17, the metal film 62b is removed according to the resist pattern 64. That is, the alignment mark 62 is formed on the glass substrate 602.
Next, as illustrated in (f) of FIG. 17, after the metal film 62b is removed, the resist pattern 64 is removed.
Lastly, as illustrated in (g) of FIG. 17, the color filter substrate 603 is formed on the glass substrate 602 and the alignment mark 62.
Alternatively, the alignment marks 61 and 62 as shown in FIGS. 15 and 16 can be formed in the following manner. FIG. 18 is a view for describing the steps of forming the alignment marks 61 and 62.
First, as illustrated in (a) of FIG. 18, a metal film 62b is stacked on the glass substrate 602. The metal film 62b is stacked under the condition where a stack prevention mask 65 is provided above the alignment region of the protection film 601 so that no metal film 62b is stacked above the alignment region. Since the alignment region of the protection film 601 is hidden behind the stack prevention mask 65 when viewed from above, no metal film 62b is stacked above the alignment region.
Next, as illustrated in (b) of FIG. 18, after the metal film 62b is stacked, the stack prevention mask 65 is removed.
Next, as illustrated in (c) of FIG. 18, a resist pattern 64 is formed on the metal film 62b. The resist pattern 64 is a pattern for forming the alignment mark 62. A design pattern of the resist pattern 64 is aligned with the alignment mark 61 which serves as a reference.
Next, as illustrated in (d) of FIG. 18, the metal film 62b is removed according to the resist pattern 64. That is, the alignment mark 62 is formed on the glass substrate 602.
Next, as illustrated in (e) of FIG. 18, after the metal film 62b is removed, the resist pattern 64 is removed.
Lastly, as illustrated in (f) of FIG. 18, the color filter substrate 603 is formed on the glass substrate 602 and the alignment mark 62.